Mail domains

A mail domain is the part of an email address after the @ symbol. It indicates the server where the mailbox is located. For example:

• for user@gmail.com the mail domain is gmail.com
• for user@example.com the mail domain is example.com

In the ispmanager panel, a mail domain serves four main purposes:

• unites all mailboxes under a single name. For example, within the example.com domain, you can create mailboxes like info@example.com, support@example.com, and others
• applies uniform security settings to all mailboxes in the domain. It uses Greylisting blacklists and whitelists, filters spam with SpamAssassin, and checks attachments with ClamAV
• determines what to do with emails to non-existent addresses: display an error, delete the email, or forward it to another address
• uses an SSL certificate to encrypt email traffic

Requirements

To work with mail domains, install a mail server.

Creating a mail domain

1. Log in to ispmanager with the desired account.
2. Go to the Mail section.
3. On the toolbar, click Mail domains.
4. On the toolbar, click Create a mail domain.
5. Fill in the fields:
   • Name — the name of the mail domain
   • Owner — the user who will own the mail domain. This field is not available to users.
   • IP address — select the address emails will be sent from.
   • Default action — the action performed by the mail server upon receiving an email sent to a non-existent mailbox for this email domain:
     • Report error — the sender will receive an error stating that the mailbox does not exist.
     • Ignore and delete — the sender will receive an error stating that the mailbox does not exist. The email will be accepted and deleted by the mail server.
     • Forward to address — the email will be sent to the email address specified in the Forward to field.

     • Forward to domain — the mail server will retry searching for a mailbox from the mail domain specified in the Redirect to field.

       Redirection will not work if you specify a mailbox alias in the Redirect to field.

6. If necessary, set additional options:
   • Enable Greylisting — a mail filter for spam protection via Greylisting. Once activated, it becomes available for mailboxes in the mail domain.
   • Enable SpamAssassin — a mail filter for spam protection via SpamAssassin. Once activated, it becomes available for mailboxes in the mail domain.
   • Enable virus scanning — email scanning via ClamAV antivirus software.
   • Enable DKIM for a domain — a technology for protecting mailboxes from phishing. It verifies that emails are sent from the specified mail address. Once activated, a TXT record is automatically created for the mail domain:
     • DKIM selector — an identifier published in the DNS records of this domain. It allows receiving mail servers to determine which key to use when verifying the DKIM signature. Default value: dkim

     • DKIM key length — the length of the generated key. Available values: 1024 and 2048

       More about DKIM keys

       The record is specified in the format: KEY_NAME._domainkey.YOUR_DOMAIN. Record example: dkim._domainkey.example.com.

       Record parameters:

       • v — protocol version. Required tag. Always set to DKIM1
       • h — hash algorithm for transmitted data. Default: h=sha256. We do not recommend using h=sha1
       • k — cryptographic key type. Default: k=rsa
       • s — selector that specifies the service type. Multiple selectors can be specified. Examples: s=email (mail), s=* (all services)
       • p — generated public key in Base64 encoding of 1024 or 2048 characters. Required tag

       Parameters are specified separated by the ";" symbol. Default value: v=DKIM1; h=sha256; k=rsa; s=email; p=PUBLIC_KEY.

       Keys are generated using the opendkim-genkey utility under the Exim user-owner of the mail domain:

       bin/sh -c /usr/sbin/opendkim-genkey\ -D\ /etc/EXIM_DIRECTORY/ssl\ -d\ MAIL_DOMAIN_NAME\ -s\ dkim\ -r

       The generated files are stored in the following directory:

       • for RHEL-based operating systems: /etc/exim/ssl
       • for Debian-based operating systems: /etc/exim4/ssl

       Directory files:

       MAIL_DOMAIN_NAME.private — private key

       MAIL_DOMAIN_NAME.txt — public key

   • Enable DMARC for domain — a technology for protecting your email domain using DMARC. This sets the incoming email verification policy for the domain. Once enabled, a TXT record is automatically created for the email domain. The value is generated using a template from the DNS management → → DMARC record field.
   • Secure connection (SSL) — secures data transmission and encryption. A mail domain certificate is required for activation. This option is available if the mail domain owner has no restrictions on using SSL.
     • Certificate alias — the default is: mail.MAIL_DOMAIN_NAME
     • SSL certificate:
       • New self-signed — a free, untrusted certificate. For public servers, the connection will be considered unsecure.
       • New Let's Encrypt certificate — a free, trusted certificate.
     • Email — the email address of the contact person.
7. Save the changes.

Viewing mail domains

Created mail domains appear in the list in the Mail domains section. Viewing available:

• for a user — their own mail domains
• for a reseller — the mail domains of the reseller's users
• for an administrator — all mail domains

A reseller or administrator can configure the display of mail domains for a specific user. To do this:

1. Select the user's email domain.
2. Click .
3. In the context menu, select Filter by user.

Available actions

Button	Description
	Change mail domain settings
	Delete a mail domain. Deleting a mail domain will clear your mailboxes, free up space, and restore disk quotas. Without a backup, it will be impossible to recover deleted emails.
	Enable mail domain
	Disable the mail domain. All mailboxes and associated features will be unavailable.
	Log in to the account with mail domain owner rights. Available for reseller-level accounts and above.
	Change the mail server SSL certificate
	Change the owner of a mail domain

Configuration files

Log

Creation, modification of parameters, deletion and other actions with mail domains are recorded in the main ispmanager log — /usr/local/mgr5/var/ispmgr.log.